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Cholinergic receptor activation on epithelia protects against cytokine‐induced barrier dysfunction
Author(s) -
Dhawan S.,
Hiemstra I. H.,
Verseijden C.,
Hilbers F. W.,
Velde A. A.,
Willemsen L. E. M.,
Stap J.,
Haan J. M.,
Jonge W. J.
Publication year - 2015
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/apha.12469
Subject(s) - cholinergic , muscarinic acetylcholine receptor m3 , muscarinic acetylcholine receptor , acetylcholine , muscarinic acetylcholine receptor m2 , muscarinic acetylcholine receptor m5 , myosin light chain kinase , muscarinic acetylcholine receptor m1 , chemistry , microbiology and biotechnology , endocrinology , medicine , biology , receptor , myosin
Aim Various types of cholinergic receptors are expressed on intestinal epithelia. Their function is not completely understood. We hypothesize that cholinergic receptor activation on epithelium may serve a protective function in cytokine‐induced barrier dysfunction. Methods The effect of cholinergic receptor activation on cellular barrier function in epithelial cells was assessed by measuring electrical impedance, and by determining para‐cellular transport in transwell experiments. Cell lysates treated with cytokine and/or cholinergic agonists were analysed for cyto‐ and chemokine production, and tight junction ( TJ ) protein rearrangement was assessed. Primary colonic epithelial cells were isolated from surgically resected colon tissue of patients with inflammatory bowel disease. Results IL ‐1 β induced production of chemokines ( CXCL ‐1, CXCL ‐10, IL ‐8, CCL ‐7) and led to a rearrangement of TJ proteins (occludin and ZO ‐1). This response was inhibited by pre‐treatment with muscarinic, rather than nicotinic, acetylcholine receptor agonists. Treatment with IL ‐1 β enhanced paracellular permeability (4kD dextran) and reduced impedance across the monolayer, which was counteracted by pre‐incubation with acetylcholine, or muscarinic receptor agonist bethanechol. The protective effect of acetylcholine was antagonized by atropine, underscoring muscarinic receptor involvement. IL ‐1 β induced transcription of myosin light chain kinase and phosphorylation of myosin light chain, and this cytokine‐induced phosphorylation of MLC was inhibited by muscarinic receptor agonists. Furthermore, in epithelial cells from resection material of patients with Crohn's disease and ulcerative colitis, high expression of CXCL ‐8 was associated with a reduced choline acetyl transferase expression, suggesting an aberrant epithelial production of AC h in inflammatory context. Conclusion Acetylcholine acts on muscarinic receptors on epithelial cells to maintain epithelial barrier function under inflammatory conditions.